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<a name="boost.interprocess.interprocess_semaphore"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2><span class="refentrytitle">Class interprocess_semaphore</span></h2>
<p>boost::interprocess::interprocess_semaphore</p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../interprocess/indexes_reference.html#header.boost.interprocess.sync.interprocess_semaphore_hpp" title="Header &lt;boost/interprocess/sync/interprocess_semaphore.hpp&gt;">boost/interprocess/sync/interprocess_semaphore.hpp</a>&gt;

</span>
<span class="keyword">class</span> <a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a> <span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
  <span class="comment">// <a class="link" href="interprocess_semaphore.html#boost.interprocess.interprocess_semaphoreconstruct-copy-destruct">construct/copy/destruct</a></span>
  <a class="link" href="interprocess_semaphore.html#idm30895-bb"><span class="identifier">interprocess_semaphore</span></a><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span><span class="special">)</span><span class="special">;</span>
  <a class="link" href="interprocess_semaphore.html#idm30902-bb"><span class="special">~</span><span class="identifier">interprocess_semaphore</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>

  <span class="comment">// <a class="link" href="interprocess_semaphore.html#idm30861-bb">public member functions</a></span>
  <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#idm30862-bb"><span class="identifier">post</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#idm30869-bb"><span class="identifier">wait</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  <span class="keyword">bool</span> <a class="link" href="interprocess_semaphore.html#idm30876-bb"><span class="identifier">try_wait</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> TimePoint<span class="special">&gt;</span> <span class="keyword">bool</span> <a class="link" href="interprocess_semaphore.html#idm30883-bb"><span class="identifier">timed_wait</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">TimePoint</span> <span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.19.17.3.63.4.4"></a><h2>Description</h2>
<p>Wraps a <a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a> that can be placed in shared memory and can be shared between processes. Allows timed lock tries </p>
<div class="refsect2">
<a name="id-1.3.19.17.3.63.4.4.3"></a><h3>
<a name="boost.interprocess.interprocess_semaphoreconstruct-copy-destruct"></a><code class="computeroutput">interprocess_semaphore</code> 
        public
       construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><a name="idm30895-bb"></a><span class="identifier">interprocess_semaphore</span><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> initialCount<span class="special">)</span><span class="special">;</span></pre>
<p>Creates a <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> with the given initial count. <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> if there is an error. </p>
</li>
<li class="listitem">
<pre class="literallayout"><a name="idm30902-bb"></a><span class="special">~</span><span class="identifier">interprocess_semaphore</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>
<p>Destroys the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>. Does not throw </p>
</li>
</ol></div>
</div>
<div class="refsect2">
<a name="id-1.3.19.17.3.63.4.4.4"></a><h3>
<a name="idm30861-bb"></a><code class="computeroutput">interprocess_semaphore</code> public member functions</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><span class="keyword">void</span> <a name="idm30862-bb"></a><span class="identifier">post</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>
<p>Increments the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> count. If there are processes/threads blocked waiting for the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>, then one of these processes will return successfully from its wait function. If there is an error an <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> exception is thrown. </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">void</span> <a name="idm30869-bb"></a><span class="identifier">wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>
<p>Decrements the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>. If the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> value is not greater than zero, then the calling process/thread blocks until it can decrement the counter. If there is an error an <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> exception is thrown. </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="idm30876-bb"></a><span class="identifier">try_wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre>
<p>Decrements the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> if the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>'s value is greater than zero and returns true. If the value is not greater than zero returns false. If there is an error an <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> exception is thrown. </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> TimePoint<span class="special">&gt;</span> <span class="keyword">bool</span> <a name="idm30883-bb"></a><span class="identifier">timed_wait</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">TimePoint</span> <span class="special">&amp;</span> abs_time<span class="special">)</span><span class="special">;</span></pre>
<p>Decrements the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> if the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>'s value is greater than zero and returns true. Otherwise, waits for the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> to the posted or the timeout expires. If the timeout expires, the function returns false. If the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> is posted the function returns true. If there is an error throws sem_exception </p>
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<td align="right"><div class="copyright-footer">Copyright © 2005-2015 Ion Gaztanaga<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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